Aug 3, 2016 · HDPE (High Density Polyethylene) Plastic Sheet 1/4" x 12" x 24" Black Brand: Polymersan 88 ratings 13 answered questions Currently unavailable. We don't know when or if this item will be back in stock. About this item The linear dimensions of our sheets are nominal and they have a tolerance of +-1/8" in each direction (length and width).